Oil circuit breaker interrupter having keyed separable plates with laminar flow preventing projections and connection means for connecting the interrupter tube and stationary contacts within the interrupter tube to a common support



Jan. 2, 1968 D. MCCONNELL 3,361,885

OIL CIRCUIT BREAKER INTERRUPTER HAVING KEYED SEPARABLE PLATES WITH LAMINAR FLOW PREVENTING PROJECTIONS AND CONNECTION MEANS FOR CONNECTING THE INTERRUPTER TUBE AND STATIONARY CONTACTS WITHIN THE INTERRUPTER TUBE TO A COMMON SUPPORT Filed Feb. 26, 1965 5 Sheets-Sheet l WIII-I-III J 3 INVENTOR.

Zoe/M: a warm M511 Jan. 2, 1968 0. M CONNELL 3,361,885

OIL CIRCUIT BREAKER INTERRUPTER HAVING KEYED SEPARABLE PLATES WITH LAMINAR FLOW PREVENTING PROJECTIONS AND CONNECTION MEANS FOR CONNECTING THE INTERRUPTER TUBE AND STATIONARY CONTACTS WITHIN THE INTERRUPTER TUBE TO A COMMON SUPPORT Filed Feb. 26, 1965 5 Sheets-Sheet 2 I? 5.20. 2-? 5.21. JTGJE E15.

3,361,885 BITE PLATES Y CONTACTS PORT 3 Sheets-Sheet 5 .z c3 E"D.

L. D. M CONNELL OIL CIRCUIT BREAKER INTERRUPTER HAVING KEYED SEPARA WITH LAMINAR FLOW PREVENTING PROJECTIONS AND CONNECTION MEANS FOR CONNECTING THE INTERRUPTER TUBE AND STATIONAR WITHIN THE INTERRUPTER TUBE TO A COMMON SUP 1965 Jan. 2, 1968 Filed Feb. 26,

INVENTOR. /0eA a /%(a/1 4 zz avzazzwz /Q&2

United States Patent OIL CIRCUHT BREAKER INTERRUPTER HAVING KEYED SEPARABLE PLATES WITH LAMINAR FLOW PREVENTING PROJECTIONS AND CON- NECTION MEANS FOR CONNECTING THE RN- TERRUPTER TUBE AND STATIONARY CON- TACTS WlTHIN THE ItNTERRUPTER TUBE TO A COMMON SUPPORT Lorne D. McConnell, Sierra Madre, Calili, assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed Feb. 26, 1965, Ser. No. 435,637 7 Claims. (Cl. 2tl015t)) ABSTRACT OF THE DISCLOSURE An oil circuit breaker interrupter in which a stack of interrupter plates are contained in an insulation tube with the base defining exhaust channels leading to ports in the interrupter tube. The stack of plates are held together by a rod which permits separation of the plates by a distance equal to the depth of a keying means between the plates so that the plates can be separated and swivelled with respect to one another for inspection without complete disassembly. The stack of plates and the interrupter tube receive a central stationary contact support from a common insulator bushing support, with the insulation tube spaced from the common support by a fiat spacer having radial arms to permit a path of oil flow into the interior of the interrupter tube. The exhaust plates of the stack are formed with two arcuate projections symmetrically disposed about the lateral exhaust channel and which define interference pockets for preventing laminar flow of oil around the interior of the plate.

This invention relates to an interrupter structure for oil blast circuit breakers, and more specifically relates to a novel assemblage of novelly fomed plate elements for forming the interrupter structure.

Interrupter structures for oil circuit breakers are generally well known in the art, and are formed of elongated insulation tubes having a plurality of transverse plates therein which define orifices leading to exhaust ports in the interrupter structure wall. This entire structure is immersed in oil within a tank, and an elongated contact rod extends generally centrally of the interrupter structure and through aligned openings in the interrupter structure plates to engage a stationary contact at the top of the interrupter structure.

In order to interrupt current flow between stationary and movable contacts, the movable contact is rapidly moved downwardly with the are drawn between the movable and stationary contacts being extinguished by the flow of oil across the arc and out the exhaust ports in the interrupter structure.

The interrupter structure of the present invention provides a novel fixed opening at the top of the interrupting chamber by means of a novel spacer structure. This forms 'an oil inlet passage through which oil can be drawn by suction as the contact rod is withdrawn out of the contact finger assembly within the interrupter structure. It further serves as an oil outlet to relieve the interrupting chamber of excessive pressure during interrupting conditions.

When acting as an oil inlet passage, the novel spacer structure permits oil flow in a downward direction from areas external of the interrupter structure to provide a sweeping action through, between and below the main fingers of the stationary contacts which encircle the tip of the movable contact rod. This arrangement assists in the interruption of any transfer arcs formed between the main fingers of the stationary contact and the moving 3,361,885 Patented Jan. 2, 1968 contact rod, thus providing improved control of the initiation of the main arc on the extending arcing contact finger of the stationary contact assembly. This downward oil flow permitted by the novel spacer structure also eliminates or minimizes the inward suction of oil through the exhaust passages of the interrupter which can cause an inward or side motion of the are within the interrupter structure, or the arc gases, thus interfering with arc control and resulting in inadequate sweeping of arc gases thus displaced, and in poor interrupting performance.

In combination with this novel spacer structure, the top plate of the interrupter assembly is provided with a circular depression in the top surface thereof which is external of the outer diameter of the stationary contact finger cluster, and is immediately adjacent to the end of the main stationary contacts. This assists in directing oil flow during interrupting conditions past the lower ends of the contact fingers to assist in the transfer of current to the arcing contact member.

This novel circular depression further acts to provide a bafile against the ejection of ionized gases outwardly and radially past the lower ends of the contact fingers. Such ejection and subsequent pocketing of gases can be injurious to insulation strength following interruption at a current zero.

As a further feature of the invention, a novel exhaust plate structure is provided within the interrupter assembly which is disposed immediately to the rear and adjacent each exhaust opening, and has an inner contour to form oil reservoirs immediately adjacent the exhaust openings. The novel exhaust plate is then provided with three internal projections to counteract any tendency for circular motion of oil, are or arc gases within the reservoir. Moreover, these three projections are so arranged that they prevent the possibility of laminar hydraulic flow along the full vertical faces of the exhaust plate in that two of the sections project toward the exhaust opening.

The novel exhaust plate is further provided with novel raised portions on either side of the exhaust opening to provide positive keying of the exhaust plate to the plates above and below it, and at the same time provide a baffle against the ejection of hot arc gases between the plates.

The complete assembly of plates of the interrupter assembly are then held together by a single rod structure which retains the plates in a pre-assembled relationship with an interchange in the plates being prevented. This novel rod, which is preferably made of a thermoplastic material, is headed by heating the rod in a pocket in the lower plate in such a way that disassembly of the complete interrupter assembly plates is prevented, while the rod permits sumcient flexibility of the assembly so that the plates can be slightly separated axially so that the package may be opened at any joint and the sections on either side of the opening can be swung radially with respect to one another for inspection and cleaning of all parts.

As a further feature of the invention, the interrupting plates are formed of an acetyl resin material which is injection-molded to form the plate structure. More particularly, acetyl resin materials of the type used for the novel plates is known by the tradename Celcon, which is a trademark of the Celanese Corporation.

I have found that this material is ideally adapted for use in interrupting devices after learning that there is an absence of carbonization after arcing over the material; a release of gases which are beneficial to the interrupting process during arcing; and its ability to be molded to intricate forms at low cost.

Accordingly, a primary object of this invention is to provide a novel assemblage of plates for an interrupter structure.

Another object of this invention is to provide a novel spacer device for an interrupter structure which forms a fixed opening at the top of the interrupter chamber to serve as an oil inlet and oil outlet passage.

Yet another object of this invention is to provide a novel effective means for interrupting transfer arcs formed between the main stationary fingers of the stationary contact and the moving contact rod to provide improved control of initiation of the main arc to the extending arcing contact finger of the stationary contact assemblage.

Still another object of this invention is to prevent the inward flow of oil through the exhaust passages of an interrupter structure which upsets control of the arc and causes inadequate sweeping of arc gases.

Yet another object of this invention is to provide a novel top plate structure for an interrupter assembly which has a circular depression therein lying immediately adjacent the main stationary contact fingers and having a diameter slightly greater than the diameter of the main contact fingers.

Another object of this invention is to provide a novel top plate structure which defines a bafile against the ejection of ionized gases outward radially past the lower ends of the stationary contact fingers.

A. further object of this invention is to provide a novel exhaust plate structure for an interrupter assembly which has a plurality of interior projections within an oil reservoir immediately adjacent an exhaust opening wherein the projections defeat the circular motion of oil within the reservoir.

A further object of this invention is to provide a novel exhaust plate structure for interrupter structures wherein raised keying projections are provided adjacent each of the exhaust openings for keying the exhaust plate to its adjacent plates, which projections further serve as a baflie to the ejection of hot arc gases between the exhaust plate and the plates adjacent thereto.

Yet another object of this invention is to provide a novel rod structure for securing the plates of an interrupter structure together which permits the side opening of the plate package.

Still another object of this invention is to use an acetyl resin material for the interrupting plates of an interrupter structure.

These and other objects of this invention will become apparent from the following description when taken in connection with the drawings, in which:

FIGURE 1 is a side cross-sectional view of the interrupter structure of the present invention.

FIGURE 2 is a bottom plan view of the top plate of FIGURE 1.

FIGURE 3 is a cross-sectional view of FIGURE 2 taken across the lines 33 in FIGURE 2.

FIGURE 4 is a top view of one of the exhaust plates of FIGURE 1.

FIGURE 5 is a cross-sectional view of FIGURE 4 taken across the lines 55, particularly to show the keying projections in the exhaust plate of FIGURE 4.

FIGURE 6 is a cross-sectional view of FIGURE 4 taken across the lines 6-6 in FIGURE 4.

FIGURE 7 is a top view of the top interrupter plate of FIGURE 1.

FIGURE 8 is a cross-sectional view of the interrupter plate of FIGURE 7 taken across the lines 8-8 in FIG- URE 7.

FIGURE 9 is a front view of FIGURE 7 and particularly illustrates the keying channels in the plate of FIG- URE 7.

FIGURE 10 is a top view of the second interrupter plate of FIGURE 1.

FIGURE 11 is a cross-sectional view of FIGURE 10 taken across the lines II-11 in FIGURE 10.

FIGURE 12 is a top view of the third of the interrupter plate series of FIGURE 1.

FIGURE 13 is a cross-sectional view of FIGURE 12 taken across the lines 1313 in FIGURE 12.

FIGURE 14 is a top view of the lower ring of the interrupter assembly of FIGURE 1.

FIGURE 15 is a bottom view of the lower ring of FIG- URES 1 and 14.

FIGURE 16 is a cross-sectional view of FIGURE 14 taken across the lines I6I6 in FIGURE 14.

FIGURE 17 is a top view of the novel spacer used atop the interrupter assembly of FIGURE 1.

FIGURE 18 is a perspective View of the assembled stack of plates of the present invention.

FIGURE 19 is a perspective view similar to FIGURE 18 where the plates have been parted and rotated about their alignment rod to permit inspection of the plate surfaces.

FIGURE 20 is a perspective view similar to FIGURES 18 and 19 where only the top plate has been rotated to an inspection position.

Referring first to FIGURE 1, I have shown therein in cross-sectional view the assembly of the novel interrupter structure. This interrupter structure is for a purpose well known to those skilled in the art with all of the auxiliary equipment to be used with the interrupter structure being well known. By way of example, such equipment can be found in copending application Ser. No. 67,125, filed Nov. 3, 1960, entitled, Tank Structure for Oil Circuit Breaker, in the name of James R. McCloud, and assigned to the assignee of the present invention, now abandoned. Thus, the interrupter structure is carried from a conductive adapter structure 3t) which is connectable to the end of an insulator bushing which suspends the complete structure beneath oil in an oil filled tank.

The adapter 30 is connected to a conductive stud 31 which is bolted to a conductive support ring 32. A stationary contact structure generally shown as structure 33 is then secured to the conductive ring 32 by a bolt 34 in the usual manner. The stationary contact cluster 33 is of the well known type, and is provided with a plurality of circularly arranged main contact fingers such as contact fingers 35, 36, 37 and 38.

An arcing contact finger 39 is then provided which extends lower than the main contact fingers 35 through 38 along with three other main contact fingers not seen in FIGURE 1, but which complete a circular enclosure.

Each of the stationary contact fingers are then secured to a main contact hub 40 in the usual manner, as shown, for example, by screws 41 and 42 which extend through leaf springs 43 and 44 which press against insulated buttons 45 and 46 of contact finger 35 and the main flexible conductor 47 which electrically connects and mechanically supports contact finger 35 of hub 40.

The springs 43 and 44, of course, bias the contact finger inwardly to obtain sufiicient contact pressure with respect to an elongated movable contact (not shown) which enters the interrupter structure from the bottom thereof and terminates within the circularly arranged stationary contact fingers.

A main interrupter tube 50, which may be of any suitable insulation material, then has an internal thread 51 which threadably receives a support ring 52 having a suitable external thread and which is directly connected to ring 32 in the usual manner. By way of example, a plurality of bolts such as bolts 52a and 52b extend from and are integral with ring 52 and are captured by and are passed through suitable openings in ring 32 and are captured by suitable nuts such as nuts 52c and 52d, respectively.

The interrupter tube 50 is further provided with a plurality of exhaust ports 53 through 58 which are arranged along one side of the wall of interrupter tube 50. Since the elongated stationary arcing contact finger 3% is to be located adjacent the side of tube 50 having the ports 53 through 58 in the wall thereof, a suitable keying means 59 is interposed between support member 32 and the main contact assembly 33. A second pressure ring 60 is then threaded into the thread 51 of interrupter tube 50 and is connected to ring 52 through a fiat spring 61, again in the usual manner.

In accordance with a first feature of the invention, a spacer 70 in interposed between the bottom surface of disk 32 and the upper surface of contact tube 33 and the end of tube 50. Thus, the spacer ring 70 which is best shown in FIGURE 17, defines an annular channel 71 extending around the periphery of the top of tube 50 which permits oil flow from the exterior of the interrupter assembly to the interior of the interrupter assembly.

It will be noted from FIGURE 17 that the spacer 70, which may be of any suitable material such as a silverplated copper, is provided with a central opening 71 for receiving bolt 34 of FIGURE 1, and is provided with four outwardly extending legs 72, 73, 74 and 75. Each of legs 72 through 75 then have respective openings therein such as openings 76, 77, 78 and 79 which permit passage of bolts from ring 52 through ring 32 for securing the interrupter structure to the ring 32. Thus, the bolts 52a and 52b, for example, can pass through openings 77 and 78, respectively. Note that the spacer 70 of FIGURE 1 is shown in FIGURE 1 in a cross-sectional view across the lines 1-1 in FIGURE 17.

The function of spacer 70, as pointed out above, is to provide an oil inlet or outlet passage through which oil can be moved by high or low pressure conditions on the interior of the interrupter structure from areas external of the interrupter structure. Thus, when the contact rod is withdrawn from the contact finger assembly 33, oil can fiow through orifice 71 due to the decrease in pressure within the interrupter structure. Oil fiow is then initiated downwardly through the interrupter structure to provide a sweeping action through, between and below the main fingers such as fingers 35 through 38 of the stationary contact assembly 33. This will assist in the interruption of any transfer arcs formed between one of the main fingers 35 through 38 and the moving contact rod, thus forcing and improving the control of the initiation of the main are from the extending arcing contact finger 39.

This downward oil flow from inlet 71 also eliminates or minimizes the inward suction of oil through the exhaust ports 53 through 58 of interrupter 50 which would occur .without this top inlet vent. This inward flow of oil through ports 53 through 58 can cause the inward motion of an are along the interrupting chamber, resulting in poor are control and poor sweeping of the are thereby to adversely affect interrupting performance.

A stack of plates 102 through 116 are then compressed between the throat bushing 100 and an upper pressure n ring 117 which bears on top of plate 102 and is pressed downwardly by pressure ring 60. These plates, which will be described more fully hereinafter, are aiigned with respect to one another by a novel rod 118 which extends through plates 103 through 114 and terminates in plates 102 and 115.

The top plate 102 of FIGURE 1 is best shown in FIG- URES 2 and 3 and may be formed of any suitable fiber or other insulation material and has a key-shaped opening 120 therein, the upper part of which receives the elongated contact rod while the lower slot-shaped sec tion 121 receives the extending interrupting finger 39 of the main stationary contact assembly.

The lower surface of plate 102 then has two arcuate keying depressions 122 and 123 therein which are adjacent the passage 124 (FIGURE 1) which leads to port 53.

As will be shown more fully hereinafter, the arcuate channels 122 and 123 receive keying projections from plate 103 which seal off the space between plates 103 and 102 in the region of the exhaust passage 124. The rearward portion of plate 102 then has a threaded opening 130 therein which could be slotted by slot 131 to the edge of the plate. Threaded opening 130, as will be 6 described more fully hereinafter, threadably receives the upper end of rod 118 of FIGURE 1.

Plate 102 then has a circular depression therein which is arranged to have a diameter slightly greater than the outer diameter of the stationary contact finger cluster and is located immediately adjacent the bottom of the main stationary contact fingers.

This novel arrangement, in cooperation with the novel spacer 70 discussed above, aids in directing oil flow from channel 71 past the lower ends of the main contact fingers such as fingers 35 through 38 to assist in the transfer of current to the arcing contact finger 39 during interrupting conditions.

This novel arrangement further provides a bafile against the ejection of ionized gases outward and radially past lower ends of contact fingers 35 through 38. This ejection of ionized gases could cause pocketing of gases which could deleteriously afiect insulation strength following an interruption at current zero.

Immediately below plate 102, and located adjacent each of exhaust ports 53 through 53, there are provided a plurality of exhaust plates 103, 105, 107, 109, 111 and 113, respectively. Each of these plates are of identical construction and are best shown in FIGURES 4 through 6 for plate 103.

As shown in FIGURES 4 and 6, plate 102 has a rearwardly disposed opening therein for receiving rod 118, and is provided with two extending arcuate sections such as sections 141 and 142 on each of its surfaces.

Thus, as shown in FIGURE 5, a second extending arcuate section 143 is provided on the bottom surface of plate 103, and is aligned with arcuate section 141. In a similar manner, another T-shaped section will be on the bottom surface of plate 103 aligned with arcuate section 142.

The plate 103 defines an oil reservoir aligned with exhaust channel 124 and port 53. In a similar manner, each of plates 105, 107, 109, 111 and 113 define oil reservoirs immediately adjacent ports 54 through 58, respectively.

Each of these plates, as typified in FIGURE 4 for plate 103, is then provided with three projecting sections 145, 14% and 147 which are adapted to prevent a circulating motion of oil within the reservoir defined by the plate.

In particular, projecting sections 145and 147 face toward the port 53 and are proportioned with respect to the arc position to eliminate the formation of zones within the forward section of the reservoir where sweeping or are products is not affected. That is to say, the projecting sections prevent the possibility of laminar hydraulic flow along the interior vertical faces of the exhaust plates.

The keying projections 141 and 142 are then seen to lock directly into the keying depressions 122 and 123, respectively, of the top plate of FIGURE 1. This type of positive keying between the adjacent plates is continued throughout the structure for all adjacent plates, and not only locks the adjacent plates in appropriate spacial relation with respect to one another, but further serves as a battle against the ejection of hot arc gases between the plates and radially outward at the inside diameter of tube 50.

The next lowest plate of the assembly of FIGURE 1 is the interrupter plate 104, best shown in FIGURES 7, 8 and 9. Plate 104 is again provided with an opening 150 for receiving rod 11 and defines an interior chamber 151 having beveled sides 152 and 153 on its front splitter section.

Plate 104 is then provided with arcuate keying channels 154 and 155 which receive keying projections 143 and another, not shown, of plate 103. A further pair of arcuate depressions 156 and 157 then receive keying extensions of the next adjacent exhaust plate 105.

The next lower plate of the stack is the plate 106, which is best shown in FIGURES l0 and 11. It will be noted that plate 106 and plates 110 and 112 are identical in construction. Each of these plates, as shown for plate 106 of FIGURE 10, has an opening 160 for receiving rod 118 and a central opening 161 having a pointed front surface 162 for improved arc positioning purposes. They are then provided with suitable arcuate keying depressions such as the keying depressions 163 and 164 for receiving associated keying extensions such as the extensions in exhaust plates 105 and 107.

The next lower plate 108 is best shown in FIGURES 12 and 13, and is identical to plate 114. Plate 108 has an opening 170 therein for receiving rod 118, and a central opening 171 for receiving the movable contact rod. Suitable keying depressions such as arcuate depressions 172 and 173 are also provided for receiving keying projections from exhaust plates 107 and 109, respectively.

The last plate of the stack is the ring 115 which is best shown in FIGURES 14, 15 and 16. As shown in these figures, ring 115 has a central opening 100 therein which has a shoulder 181 which serves to retain support rod 113 in position, as will be described more fully hereinafter.

The upper surface of ring 115 is then provided with arcuate depressions 182 and 183 which serve to receive cooperating extensions in exhaust plate 113. The bottom surface of ring 115 is provided with an extending key section 134 which cooperates with a registering depression 'in plate 116 so that plate 116 can be suitably keyed with respect to the plate assembly. Note that plate 116 has a projection 184 which keys into throat bushing 100. Throat bushing 100 has a key slot, shown in FIGURE 1 in the lower left-hand side, which accepts a key formed in tube 50, which locates oil plates in respect to port openings in tubes.

As is apparent from the foregoing description, each of plates 102 through 115 can be secured to one another as a subassembly by means of the rod 110 which extends through aligned openings in each of these plates.

More particularly, the rod 118 is threaded into plate 102 and the remaining plates 103 through 115 are then assembled over rod 113. The rod 118 which is of a suitable thermoplastic material is then headed as by heating to form the enlarged head 190, as best shown in FIGURE 1, which is captured with respect to shoulder 181, but has a limited amount of clearance to permit a limited axial separation between two adjacent plates.

This novel arrangement provides means for retaining the preassembled relationship of parts 102 through 115, but at the same time, permits sufiicient separation between any two plates so that two groups of plates can be rotated with respect to one another for purposes of inspection and cleaning.

This novel arrangement can be best understood from FIGURES l8, l9 and 20 which show a perspective view of the plate assembly. FIGURE 18 shows the subassembly of plates in their normal position with respect to one another.

As shown in FIGURE 19, when it is desired to inspect the upper surface of plate 108 or the lower surface of plate 107, it is only necessary to separate plates 107 and 108 by the limited axial motion permissible before head 190 of FIGURE 1 engages shoulder 181 which is sufficient to cause the lower keying projections of plate 107 to clear the keying depressions 172 and 173. Thereafter, the upper group of plates 102 through 107 can be rotated with respect to the lower group of plates 108 through 115 for inspection purposes.

In a similar manner, and as shown in FIGURE 20, only the upper plate 102 can be raised sufiiciently to permit it to rotate so that the lower surface of plate 102 and the upper surface of plate 103 can be inspected.

As previously indicated, the various plates of the interrupter assembly can be formed of any suitable insulation material.

As a further feature of the invention, however, I have found that when an a cetyl resin material is used for the plate material, I obtain improved results in that there is no carbonization when the plate is arced over. Moreover, this material has been found to release gases bene- 8 i ficial to the interrupting process during arcing conditions.

Finally, the material is capable of injection-molding techniques so that the intricately shaped plates can be molded at low cost. Note that all of the plates may be formed of a suitable acetyl resin, or alternatively, only selected plates may be formed of this material such as the exhaust plates 103, 105, 107, 109, 111 and 113.

The interrupter is in effect divided into three sections, each section ending with a close fit hole around the moving contact rod. These close fitting holes are found in plates 108, 11 i and throat bushing 100.

The three close fitting holes are provided to prevent the are products from the chamber above blowing downward and contaminating the oil in the chamber below before the arc is produced in the said chamber. The top two chambers have three ports each and moderate to heavy currents are interrupted in these areas.

Plate 104 has a splitter section and also provides a large oil reservoir. Plate 106 has a splitter section and is so made that the notch 162 helps position the arc toward the port (1) side of the tube while the close fit hole 161 limits the arcs movement away from the port. The second chamber formed by plates 108 through 114 is similar to the chamber above described.

The lower section is formed by plates 114-116 and bushing 100. This section is divided in turn by the close fitting hole in plate 116. This produces two oil chambers without ports, these two chambers allow low current arcs to produce moderate pressures in these areas to aid in extinguishing said low energy fault currents.

Although this invention has been described with respect to its preferred embodiments, it should be understood that many variations and modifications will now be obvious to those skilled in the art, and it is preferred, therefore, that the scope of the invention be limited not by the specific disclosure herein, but only by the appended claims.

The embodiments of the invention in which an ex- Ylusive privilege or property is claimed are defined as folows:

1. A plurality of plates for an interrupter structure and a securing rod for securing said plates together in a stacked assembly; each of said plates being generally flat and being stacked atop one another; each of said plates having an opening therethrough; each of said openings being in registry with one another; said securing rod extending through said openings in registry and terminat ing in the uppermost and lowermost plates of said assembly; means connecting one end of said rod to one of said uppermost and lowermost plates, and lost motion means connecting the other end of said rod to the other of said uppermost and lowermost plates whereby any pair of adjacent plates of said stack of plates can be axially separated from one another and rotated with respect to one another around said rod without removing said rod from said stack of plates; each of said plates having axially extending keying sections extending from their adjacent surfaces; said lost motion connecting means permitting separation between any pair of adjacent plates which is greater than the axial extension of said extending keying sections.

2. The device of claim 1 wherein said one end of said rod is directly secured to said uppermost plate; said lost motion connection means comprising said other end of said rod having an enlarged head portion on said other end of said rod; said lowermost plate having a rod head securing portion normally spaced from said enlarged head when said stack is compacted and receiving said enlarged head when said stack is opened by a predetermined distance.

3. The device of claim 1 wherein said rod is of thermoplastic material.

4. In combination, an interrupter structure, a support member for said interrupter structure, and a thin, fiat spacer having spaced extending radial portions; said interrupter structure comprising a plurality of interrupter plates and an insulation tube; said plurality of plates stacked atop one another and fixed within an axially central region of said insulation tube; said support member comprising a conductive body having an end surface; a stationary contact assembly; said stationary contact assembly being secured to the outer portion of said end surface and extending into the interior of said insulation tube and toward said interrupter structure; connection means for securing said insulation tube to said conductive body; the diameter of said radial portions of said spacer generally equal to the diameter of said insulation tube; said spacer being interposed between said insulation tube and said end surface to space the end of said tube from said end surface by a predetermined distance; the separation between said spaced extending radial portions of said spacer defining annular orifices between said end surface and said end of said tube.

5. In combination for an oil circuit breaker, a stack of plates defining an interrupter structure having an opening extending therethrough, and a stationary contact assembly; said stationary contact assembly comprising a plurality of stationary contact fingers arranged in a circle surrounding and coaxial with said opening in said interrupter structure; and support means connected between said interrupter structure and said stationary contact assembly for rigidly connecting said interrupter structure and said stationary contact assembly together; a top plate connected to the top of said stack of plates; said interrupter assembly being terminated at one end thereof by said top plate; one end of said stationary contact fingers terminating in a plane parallel to the surface of said top plate and being co-planar with said surface of said top plate; said surface of said top plate having a central depression therein; said depression being coaxial with said opening and having a diameter approximately equal to the diameter of a circle defined by the outer surface of said stationary contact fingers; and a securing rod for securing said plates together in a stacked assembly; each of said plates being generally fiat and being stacked atop one another; each of said plates having an opening therethrough; each of said openings being in registry with one another; said securing rod extending through said openings in registry and terminating in the uppermost and lowermost plates of said assembly; means connecting one end of said rod to one of said uppermost and lowermost plates, and lost motion means connecting the other end of said rod to the other of said uppermost and lowermost plates whereby any pair of adjacent plates of said stack of plates can be axially separated from one another and rotated with respect to one another around said rod without removing said rod from said stack of plates.

6. The combination substantially as set forth in claim 4 wherein said spacer is secured between said stationary contact assembly and said end surface.

7. The combination substantially as set forth in claim 4 wherein said spacer is a thin sheet of conductive material having a plurality of radially extending arms.

References Oited UNITED STATES PATENTS 2,095,729 10/1937 Beiersdorf 200-450 2,811,614 10/1957 Taylor 200 3,128,360 4/1964 Rietz 200150 FOREIGN PATENTS 73 6,991 9/1932 France.

508,683 9/1930 Germany.

927,548 5/1963 Great Britain. 1,150,135 6/1963 Germany.

870,998 6/ 1961 Great Britain.

ROBERT S. MACON, Primary Examiner. 

